Should You Pre-wet Filter Paper Before Brewing Coffee? What Are the Benefits of Wet Filter Paper and How Does It Affect Extraction?

"Wetting the filter paper before brewing" has become a habit for most people and is considered a very important detail by many. But is it really that important? Why don't many brewing masters and champions perform this operation in their published videos? This inevitably confuses many people: How can some people not wet filter paper? Can coffee brewed without wetting filter paper really taste good?

With this question in mind, let's explore how FrontStreet Coffee views this practice. First, we need to understand what benefits most people believe come from wetting filter paper!

Traditional Benefits of Wetting Filter Paper

1. Removing Paper Taste

When many instructors explain the importance of wetting filter paper, they often first mention removing the paper's inherent taste. If not removed with hot water, the paper taste will seep into the coffee liquid along with the extraction process, affecting the coffee's flavor.

2. Making Filter Paper Adhere to the Dripper

By pouring water, the filter paper adheres to the dripper, which is the second advantage of wetting filter paper. The degree of adhesion between filter paper and dripper is very important, especially for drippers like V60 that have many ribbed grooves! When the filter paper doesn't adhere properly, these grooves become useless. Therefore, many people wet the filter paper to achieve better adhesion to the dripper.

3. Preheating the Dripper

Using hot water to rinse the filter paper not only helps it adhere but also preheats the dripper. There's a temperature difference between a room-temperature dripper and hot water, which causes the hot water's temperature to be partially absorbed by the dripper when poured, resulting in some temperature reduction, which in turn affects extraction efficiency during brewing. Therefore, wetting the filter paper with hot water helps the dripper absorb heat, achieving an insulation effect.

Why These Reasons May No Longer Apply

At first glance, wetting filter paper seems quite important. However, none of the above reasons sufficiently support the notion that "modern filter paper must be wetted." Here's why!

1. Regarding the Pulp Taste of Filter Paper

Older filter papers indeed had significant pulp taste due to immature manufacturing processes. But today in 2024, most brands have developed filter papers without paper taste! By using bioactive enzymes for bleaching, the resulting filter papers have neither pulp taste nor toxic residue, so naturally no longer need to be rinsed with hot water to remove paper taste.

2. Regarding Filter Paper Adhesion

Whether filter paper adheres properly mainly depends on operational technique. If operated improperly, even with water wetting, it's difficult to make the filter paper adhere properly. But with proper technique, even without water wetting, it can achieve good adhesion due to the downward pressure of the coffee grounds.

3. Regarding Preheating the Dripper

The need for preheating arose because earlier dripper materials were primarily ceramic with insulation properties! However, today, people commonly use drippers made of resin material.

Resin material is inexpensive and has high precision, allowing for mass production. It's heat-resistant but doesn't absorb heat! Not absorbing heat means it has no insulation effect. Therefore, preheating the dripper is unnecessary for many friends using resin drippers.

More Important Considerations

Therefore, while the above three points can demonstrate the importance of wetting filter paper, they only apply to specific cases or equipment issues. When your equipment and operations don't have these three problems, wetting filter paper offers no advantages. FrontStreet Coffee believes the following two points are more worth considering when deciding whether to wet filter paper.

Filter Paper's Water Absorption

Dry filter paper, like coffee grounds, has water absorption properties. A single filter paper can absorb about 8ml of water! If we wet it in advance with water, then during the formal brewing process, the filter paper won't absorb too much coffee liquid. Until brewing is complete, the upper layer of the filter paper will remain transparent white; but if we brew without wetting the filter paper, it will absorb the extracted coffee liquid, gradually changing from pure white to the yellow color of coffee liquid.

As a result, coffee brewed without wetting filter paper might be slightly weaker than coffee brewed with wetted filter paper, because a small portion of coffee liquid is absorbed by the filter paper.

Pre-extraction of Coffee Grounds

Often, friends pour coffee grounds immediately after wetting the filter paper. Coffee extraction is the process of using water to obtain aromatic substances from coffee. If coffee grounds come into contact with water before extraction begins, doesn't this mean that这部分 coffee grounds that touched water in advance are pre-extracted?

Conclusion

Don't worry~ Although these two factors do affect coffee, FrontStreet Coffee has discovered through numerous brewing comparisons that if you don't taste and compare very carefully, you won't notice any difference. There's an impact, but it's very, very small! So, to reiterate, if your equipment and operations don't have major issues, then whether you wet your filter paper or not doesn't need to be a concern - it's entirely up to your personal preference! After all, a cup of coffee doesn't need to be too complex~

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FrontStreet Coffee
No. 10 Bao'an Front Street, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

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